Molecular biology - Molecular biology. Biochemistry and Molecular Biology - Where to Study? Applied value of molecular biology

(Molekularbiologe / -biologin)

• A type

  Profession after graduation

• Salary

  3667-5623 € per month

Molecular biologists study molecular processes as the basis of all life processes. Based on the results obtained, they develop concepts for the use of biochemical processes, for example, in medical research and diagnostics or in biotechnology. In addition, they may be involved in the manufacture of pharmaceutical products, product development, quality assurance, or pharmaceutical consulting.

Duties of a Molecular Biologist

Molecular biologists can work in different fields. For example, they relate to the use of research results for production in areas such as genetic engineering, protein chemistry or pharmacology (drug discovery). In the chemical and pharmaceutical industries, they facilitate the introduction of newly developed products from research into production, product marketing and user consulting.

In scientific research, molecular biologists study the chemical and physical properties of organic compounds, as well as chemical processes (in the field of cellular metabolism) in living organisms and publish the results of the research. In higher education institutions, they teach students, prepare for lectures and seminars, check written work and take exams. Independent scientific activity is possible only after obtaining a master's and doctoral degrees.

Where Molecular Biologists Work

Molecular biologists find jobs such as

• in research institutions, for example in the fields of science and medicine
• in higher education
• in the chemical and pharmaceutical industry
• in the departments of environmental protection

Molecular Biologist Salary

The salary received by Molecular Biologists in Germany is

• from 3667 € to 5623 € per month

(according to various statistical offices and employment services in Germany)

Tasks and responsibilities of a Molecular Biologist in detail

What is the essence of the profession of Molecular Biologist

Molecular biologists study molecular processes as the basis of all life processes. Based on the results obtained, they develop concepts for the use of biochemical processes, for example, in medical research and diagnostics or in biotechnology. In addition, they may be involved in the production of pharmaceutical products, product development, quality assurance, or pharmaceutical consulting.

Molecular biology vocation

Molecular biology or molecular genetics deals with the study of the structure and biosynthesis of nucleic acids and the processes associated with the transfer and implementation of this information in the form of proteins. This makes it possible to understand the painful dysfunctions of these functions and, possibly, to cure them with gene therapy. There are interfaces for biotechnology and genetic engineering in which simple organisms, such as bacteria and yeast, to make substances of pharmacological or commercial interest commercially available through targeted mutations.

Theory and Practice of Molecular Biology

The chemical and pharmaceutical industry offers numerous areas of employment for molecular biologists... In an industrial setting, they analyze biotransformation processes or develop and improve processes for the microbiological production of active ingredients and pharmaceutical intermediates. In addition, they are involved in the transition of newly developed products from research to production. Through their verification tasks, they ensure that production facilities, equipment, analytical methods and all steps in the production of sensitive products such as pharmaceuticals always meet the required quality standards. In addition, molecular biologists advise users on the use of new products.

For leadership positions, a master's program is often required.

Molecular Biologists in Research and Education

In the field of science and research, molecular biologists are concerned with topics such as the recognition, transport, folding, and codification of proteins in the cell. Research results, which are the basis for practical application in various fields, are published and thus made available to other scientists and students. At conferences and congresses, they discuss and present the results of scientific activities. Molecular biologists give lectures and seminars, direct scientific work and take exams.

Independent scientific activity requires a master's and doctoral degrees.

Molecular biology has experienced a period of rapid development of its own research methods, which now distinguish it from biochemistry. These include, in particular, methods of genetic engineering, cloning, artificial expression and gene knockout. Since DNA is a material carrier of genetic information, molecular biology has become much closer to genetics, and molecular genetics was formed at the junction, which is both a branch of genetics and molecular biology... Just as molecular biology widely uses viruses as a research tool, in virology, methods of molecular biology are used to solve their problems. Computing technology is involved in the analysis of genetic information, in connection with which new directions of molecular genetics have appeared, which are sometimes considered special disciplines: bioinformatics, genomics and proteomics.

History of development

This fundamental discovery was prepared by a long phase of research into the genetics and biochemistry of viruses and bacteria.

In 1928, Frederick Griffith showed for the first time that an extract of heat-killed pathogenic bacteria could transmit pathogenicity to non-hazardous bacteria. The study of the transformation of bacteria further led to the purification of the pathogenic agent, which, contrary to expectations, turned out to be not a protein, but a nucleic acid. By itself, nucleic acid is not dangerous, it only carries genes that determine the pathogenicity and other properties of the microorganism.

In the 50s of the XX century, it was shown that bacteria have a primitive sexual process, they are able to exchange extrachromosomal DNA, plasmids. The discovery of plasmids, like transformation, formed the basis of plasmid technology widespread in molecular biology. Another discovery important for methodology was the discovery of bacterial viruses and bacteriophages at the beginning of the 20th century. Phages can also transfer genetic material from one bacterial cell to another. Infection of bacteria with phages leads to a change in the composition of bacterial RNA. If, without phages, the composition of RNA is similar to the composition of bacterial DNA, then after infection the RNA becomes more similar to the DNA of a bacteriophage. Thus, it was found that the structure of RNA is determined by the structure of DNA. In turn, the rate of protein synthesis in cells depends on the amount of RNA-protein complexes. So it was formulated central dogma of molecular biology: DNA ↔ RNA → protein.

The further development of molecular biology was accompanied both by the development of its methodology, in particular, by the invention of a method for determining the nucleotide sequence of DNA (W. Gilbert and F. Senger, Nobel Prize in Chemistry, 1980), and by new discoveries in the field of studies of the structure and functioning of genes (see. History of Genetics). By the beginning of the 21st century, data were obtained on the primary structure of all human DNA and a number of other organisms that are most important for medicine, agriculture and scientific research, which led to the emergence of several new directions in biology: genomics, bioinformatics, etc.

see also

• Molecular Biology (journal)
• Transcriptomics
• Molecular paleontology
• EMBO - European Organization of Molecular Biologists

Literature

• Singer M., Berg P. Genes and genomes. - Moscow, 1998.
• Stent G., Calindar R. Molecular genetics. - Moscow, 1981.
• Sambrook J., Fritsch E. F., Maniatis T. Molecular Cloning. - 1989.
• Patrushev L. I. Gene expression. - M .: Nauka, 2000. - 000 p., Ill. ISBN 5-02-001890-2

Links

Wikimedia Foundation. 2010.

• Ardatovsky district of the Nizhny Novgorod region
• Arzamas district of the Nizhny Novgorod region

See what "Molecular biology" is in other dictionaries:

MOLECULAR BIOLOGY - studies DOS. properties and manifestations of life at the molecular level. The most important directions in M. b. are studies of the structurally functional organization of the genetic apparatus of cells and the mechanism of realization of hereditary information ... ... Biological encyclopedic dictionary

MOLECULAR BIOLOGY - explores the basic properties and manifestations of life at the molecular level. Finds out how and to what extent the growth and development of organisms, storage and transmission of hereditary information, transformation of energy in living cells and other phenomena are due to ... Big Encyclopedic Dictionary

MOLECULAR BIOLOGY Modern encyclopedia

MOLECULAR BIOLOGY - MOLECULAR BIOLOGY, the biological study of the structure and functioning of MOLECULES that make up living organisms. The main areas of study are physical and chemical properties proteins and NUCLEIC ACIDS such as DNA. see also… … Scientific and technical encyclopedic dictionary

molecular biology - section of biol., which explores the basic properties and manifestations of life at the molecular level. Finds out how and to what extent the growth and development of organisms, storage and transmission of hereditary information, transformation of energy in living cells and ... ... Microbiology Dictionary

molecular biology - - Topics of biotechnology EN molecular biology ... Technical translator's guide

Molecular biology - MOLECULAR BIOLOGY, explores the basic properties and manifestations of life at the molecular level. Finds out how and to what extent the growth and development of organisms, storage and transmission of hereditary information, transformation of energy in living cells and ... ... Illustrated Encyclopedic Dictionary

Molecular biology - a science that sets as its task the knowledge of the nature of the phenomena of vital activity by studying biological objects and systems at a level approaching the molecular level, and in some cases even reaching this limit. The ultimate goal in this ... ... Great Soviet Encyclopedia

MOLECULAR BIOLOGY - studies the phenomena of life at the level of macromolecules (hl. obr. proteins and nucleic acid) in cell-free structures (ribosomes, etc.), in viruses, as well as in cells. M.'s goal. establishing the role and mechanism of functioning of these macromolecules based on ... ... Chemical encyclopedia

molecular biology - explores the basic properties and manifestations of life at the molecular level. Finds out how and to what extent the growth and development of organisms, storage and transmission of hereditary information, transformation of energy in living cells and other phenomena ... ... encyclopedic Dictionary

Books

• Molecular cell biology. Collection of problems, J. Wilson, T. Hunt. The book by American authors is an appendix to the 2nd edition of the textbook "Molecular biology of the cell" by B. Alberts, D. Bray, J. Lewis and others. Contains questions and tasks, the purpose of which is to deepen ...

A molecular biologist is a medical researcher whose mission is, no less, to save humanity from dangerous diseases. Among such diseases, for example, oncology, which today has become one of the main causes of death in the world, is only slightly behind the leader - cardiovascular diseases. New methods of early diagnosis of oncology, prevention and treatment of cancer are a priority task of modern medicine. Oncological molecular biologists are developing antibodies and recombinant (genetically engineered) proteins for early diagnosis or targeted drug delivery in the body. Specialists in this field use the most modern achievements of science and technology to create new organisms and organic substances with the aim of their further use in research and clinical activities. Among the methods used by molecular biologists are cloning, transfection, infection, polymerase chain reaction, gene sequencing, and others. One of the companies interested in molecular biologists in Russia is PrimeBioMed LLC. The organization is engaged in the production of antibodies reagents for the diagnosis of cancer. Such antibodies are mainly used to determine the type of tumor, its origin and malignancy, that is, the ability to metastasize (spread to other parts of the body). Antibodies are applied to thin sections of the tissue under study, after which they bind in cells with certain proteins - markers that are present in tumor cells, but absent in healthy cells and vice versa. Further treatment is prescribed depending on the results of the study. Among the clients of "PrimeBioMed" there are not only medical, but also scientific institutions, since antibodies can also be used to solve research problems. In such cases, unique antibodies can be produced that can bind to the protein under study, for a specific task on a special order. Another promising area of \u200b\u200bthe company's research is targeted (targeted) drug delivery in the body. In this case, antibodies are used as transport: with their help, drugs are delivered directly to the affected organs. Thus, the treatment becomes more effective and has fewer negative consequences for the body than, for example, chemotherapy, which affects not only cancer cells, but also other cells. The profession of a molecular biologist is expected to become more and more in demand in the coming decades: with an increase in the average life expectancy of a person, the number of oncological diseases will increase. Early diagnosis of tumors and innovative treatments using substances obtained by molecular biologists will save lives and improve its quality for a huge number of people.

1. Introduction.

Subject, tasks and methods of molecular biology and genetics. The value of "classical" genetics and genetics of microorganisms in the development of molecular biology and genetic engineering. The concept of a gene in "classical" and molecular genetics, its evolution. Contribution of genetic engineering methodology to the development of molecular genetics. Applied value of genetic engineering for biotechnology.

2. Molecular basis of heredity.

The concept of a cell, its macromolecular composition. The nature of the genetic material. History of proof of the genetic function of DNA.

2.1. Various types of nucleic acids. Biological functions nucleic acids. Chemical structure, spatial structure and physical properties of nucleic acids. Features of the structure of the genetic material of pro - and eukaryotes. Complementary Watson-Crick base pairs. Genetic code. The history of decoding the genetic code. The main properties of the code: tripletness, code without commas, degeneracy. Features of the code dictionary, families of codons, semantic and “nonsense” codons. Circular DNA molecules and the concept of DNA supercoiling. DNA topoisomers and their types. Mechanisms of action of topoisomerases. DNA gyrase of bacteria.

2.2. DNA transcription. RNA polymerase of prokaryotes, its subunit and three-dimensional structures. Variety of sigma factors. Prokaryotic gene promoter, its structural elements. Stages of the transcriptional cycle. Initiation, formation of an "open complex", elongation and termination of transcription. Attenuation of transcription. Regulation of the expression of the tryptophan operon. "Ribbon switches". Transcription termination mechanisms. Negative and positive regulation of transcription. Lactose operon. Regulation of transcription in the development of the lambda phage. Principles of DNA recognition by regulatory proteins (CAP protein and lambda phage repressor). Features of transcription in eukaryotes. RNA processing in eukaryotes. Capping, splicing and polyadenylation of transcripts. Splicing mechanisms. The role of small nuclear RNAs and protein factors. Alternative splicing examples.

2.3. Broadcast, its stages, the function of ribosomes. Localization of ribosomes in the cell. Prokaryotic and eukaryotic types of ribosomes; 70S and 80S ribosomes. Morphology of ribosomes. Subdivision into subparticles (subunits). Codon-dependent binding of aminoacyl-tRNA in the elongation cycle. Codon-anticodon interaction. Involvement of the elongation factor EF1 (EF-Tu) in the binding of aminoacyl-tRNA to the ribosome. Elongation factor EF1B (EF-Ts), its function, sequence of reactions with its participation. Antibiotics affecting the stage of codon-dependent binding of aminoacyl-tRNA to the ribosome. Aminoglycoside antibiotics (streptomycin, neomycin, kanamycin, gentamicin, etc.), their mechanism of action. Tetracyclines as inhibitors of binding of aminoacyl-tRNA to the ribosome. Broadcast initiation. The main stages of the initiation process. Initiation of translation in prokaryotes: initiation factors, initiation codons, 3 ¢ -end of RNA of the small ribosomal subunit, and the Shine-Dalgarno sequence in mRNA. Initiation of translation in eukaryotes: initiation factors, initiation codons, 5 ¢ untranslated region, and cap-dependent “terminal” initiation. "Internal" cap-independent initiation in eukaryotes. Transpeptidation. Transpeptidation inhibitors: chloramphenicol, lincomycin, amycetin, streptogramins, anisomycin. Translocation. Involvement of the elongation factor EF2 (EF-G) and GTP. Translocation inhibitors: fusidic acid, viomycin, their mechanisms of action. Broadcast termination. Termination codons. Protein termination factors for prokaryotes and eukaryotes; two classes of termination factors and their mechanisms of action. Regulation of translation in prokaryotes.

2.4. DNA replication and its genetic control. Polymerases involved in replication, characteristic of their enzymatic activities. DNA fidelity. The role of steric interactions between DNA base pairs during replication. E. coli polymerases I, II and III. Polymerase III subunits. Replication fork, leading and lagging threads during replication. Fragments of Okazaki. A complex of proteins in a replication fork. Regulation of replication initiation in E. coli. Termination of replication in bacteria. Features of the regulation of plasmid replication. Bi-directional and rolling-ring replication.

2.5. Recombination, its types and models. General or homologous recombination. Double-strand DNA breaks initiating recombination. The role of recombination in post-replicative repair of double-strand breaks. Holliday structure in the recombination model. Enzymology of general recombination in E. coli. RecBCD complex. RecA protein. The role of recombination in ensuring DNA synthesis in DNA damage that interrupts replication. Recombination in eukaryotes. Recombination enzymes in eukaryotes. Site-specific recombination. Differences in molecular mechanisms of general and site-specific recombination. Recombinase classification. Types of chromosomal rearrangements carried out during site-specific recombination. The regulatory role of site-specific recombination in bacteria. Construction of chromosomes in multicellular eukaryotes using a site-specific phage recombination system.

2.6. DNA repair. Classification of types of repair. Direct repair of thymine dimers and methylated guanine. Cutting out the bases. Glycosylases. The mechanism of repair of unpaired nucleotides (mismatch repair). Selection of the DNA strand to be repaired. SOS repair. Properties of DNA polymerases involved in SOS repair in prokaryotes and eukaryotes. The concept of "adaptive mutations" in bacteria. Repair of double-strand breaks: homologous post-replicative recombination and fusion of non-homologous DNA ends. The relationship between the processes of replication, recombination and repair.

3. Mutational process.

The Role of Biochemical Mutants in Forming the One Gene - One Enzyme Theory. Classification of mutations. Point mutations and chromosomal rearrangements, the mechanism of their formation. Spontaneous and induced mutagenesis. Classification of mutagens. Molecular mechanism of mutagenesis. The relationship between mutagenesis and repair. Identification and selection of mutants. Suppression: intragenic, intergenic and phenotypic.

4. Extrachromosomal genetic elements.

Plasmids, their structure and classification. Sexual factor F, its structure and life cycle. The role of factor F in mobilizing chromosomal transfer. Formation of donors such as Hfr and F ". Mechanism of conjugation. Bacteriophages, their structure and life cycle. Virulent and moderate bacteriophages. Lysogeny and transduction. General and specific transduction. Migrating genetic elements: transposons and IS-sequences, their role in genetic exchange. DNA -transposons in the genomes of prokaryotes and eukaryotes IS-sequences of bacteria, their structure IS-sequences as a component of the F-factor of bacteria, which determines the ability to transfer genetic material during conjugation Transposons of bacteria and eukaryotic organisms Direct non-replicative and replicative mechanisms of transpositions The concept of horizontal transfer of transposons and their role in structural rearrangements (ectopic recombination) and in genome evolution.

5. Study of the structure and function of the gene.

Elements of genetic analysis. Cis-trans complementation test. Genetic mapping using conjugation, transduction and transformation. Building genetic maps. Subtle genetic mapping. Physical analysis of the structure of the gene. Heteroduplex analysis. Restriction analysis. Sequencing methods. Polymerase chain reaction. Identifying gene function.

6. Regulation of gene expression. Operon and Regulon concepts. Control at the level of transcription initiation. Promoter, operator and regulatory proteins. Positive and negative control of gene expression. Control at the level of transcription termination. Catabolite-controlled operons: models of lactose, galactose, arabinose and maltose operons. Attenuator-controlled operons: a model of the tryptophan operon. Multivalent regulation of gene expression. Global systems of regulation. Regulatory response to stress. Post-transcriptional control. Sigal transduction. RNA-mediated regulation: small RNAs, sensory RNAs.

7. Fundamentals of genetic engineering. Restriction and modification enzymes. Isolation and cloning of genes. Vectors for molecular cloning. Principles for the construction of recombinant DNA and their introduction into recipient cells. Applied aspects of genetic engineering.

and). Main literature:

1. Watson J., Ace J., Recombinant DNA: A Short Course. - M .: Mir, 1986.

2. Genes. - M .: Mir. 1987.

3. Molecular biology: structure and biosynthesis of nucleic acids. / Ed. ... - M. Higher school. 1990.

4., - Molecular biotechnology. M. 2002.

5. Spirin ribosomes and protein biosynthesis. - M .: Higher school, 1986.

b). Additional literature:

1. Khesin genome. - M .: Science. 1984.

2. Rybchin of genetic engineering. - SPb .: SPbSTU. 1999.

3. Patrushev of genes. - M .: Nauka, 2000.

4. Modern microbiology. Prokaryotes (in 2 vols.). - M .: Mir, 2005.

5. M. Singer, P. Berg. Genes and genomes. - M .: Mir, 1998.

6. Nutcrackers engineering. - Novosibirsk: From Sib. Univ., 2004.

7. Stepanov biology. The structure and function of proteins. - M .: V. Sh., 1996.

Comics for the competition "bio / mol / text": Today, the molecular biologist Test tube will guide you through the world of amazing science - molecular biology! We will begin with a historical excursion through the stages of its development and describe the main discoveries and experiments since 1933. And also we will clearly tell about the main methods of molecular biology, which made it possible to manipulate genes, change and isolate them. The emergence of these methods served as a strong impetus for the development of molecular biology. Let us also recall the role of biotechnology and touch upon one of the most popular topics in this area - genome editing using CRISPR / Cas systems.

General sponsor of the competition and partner of the Skoltech nomination -.

The sponsor of the competition is the Diaem company: the largest supplier of equipment, reagents and consumables for biological research and production.

The company was the sponsor of the Audience Award.

"Book" sponsor of the competition - "Alpina non-fiction"

1. Introduction. The essence of molecular biology

Studies the basics of the life of organisms at the level of macromolecules. The goal of molecular biology is to establish the role and mechanisms of functioning of these macromolecules on the basis of knowledge about their structures and properties.

Historically, molecular biology was formed in the course of the development of areas of biochemistry that study nucleic acids and proteins. While biochemistry studies metabolism, chemical composition living cells, organisms and the chemical processes carried out in them, molecular biology focuses on the study of the mechanisms of transmission, reproduction and storage of genetic information.

And the object of study of molecular biology is the nucleic acids themselves - deoxyribonucleic (DNA), ribonucleic (RNA) - and proteins, as well as their macromolecular complexes - chromosomes, ribosomes, multienzyme systems that ensure the biosynthesis of proteins and nucleic acids. Molecular biology also borders on research objects and overlaps with molecular genetics, virology, biochemistry and a number of other related biological sciences.

2. Historical excursion through the stages of development of molecular biology

As a separate branch of biochemistry, molecular biology began to develop in the 30s of the last century. Even then, it became necessary to understand the phenomenon of life at the molecular level in order to study the processes of transmission and storage of genetic information. It was at that time that the task of molecular biology was established in the study of the properties, structure and interaction of proteins and nucleic acids.

For the first time the term "molecular biology" was used in 1933 year William Astbury in the course of research on fibrillar proteins (collagen, blood fibrin, muscle contractile proteins). Astbury studied the relationship between molecular structure and biological, physical features these proteins. At the beginning of the emergence of molecular biology, RNA was considered a component only of plants and fungi, and DNA - only animals. And in 1935 the discovery of DNA in peas by Andrey Belozersky led to the establishment of the fact that DNA is contained in every living cell.

AT 1940 year, a colossal achievement was the establishment of a causal relationship between genes and proteins by George Beadle and Edward Tatem. The scientists' hypothesis "One gene - one enzyme" formed the basis for the concept that the specific structure of a protein is regulated by genes. It is believed that genetic information is encoded by a special sequence of nucleotides in DNA that regulates the primary structure of proteins. It was later proved that many proteins have a quaternary structure. Various peptide chains are involved in the formation of such structures. Based on this, the provision on the relationship between the gene and the enzyme has been somewhat modified, and now sounds like "One gene - one polypeptide."

AT 1944 American biologist Oswald Avery and his colleagues (Colin McLeod and McLean McCarthy) proved that the substance that causes the transformation of bacteria is DNA, not proteins. The experiment served as proof of the role of DNA in the transmission of hereditary information, crossing out outdated knowledge about the protein nature of genes.

In the early 1950s, Frederic Sanger showed that a protein chain is a unique sequence of amino acid residues. AT 1951 and 1952 years the scientist determined the complete sequence of two polypeptide chains - bovine insulin AT (30 amino acid residues) and AND (21 amino acid residues), respectively.

At about the same time, in 1951–1953 years, Erwin Chargaff formulated the rules for the ratio of nitrogenous bases in DNA. According to the rule, regardless of the species differences of living organisms in their DNA, the amount of adenine (A) is equal to the amount of thymine (T), and the amount of guanine (G) is equal to the amount of cytosine (C).

AT 1953 the genetic role of DNA has been proven. James Watson and Francis Crick, on the basis of an X-ray of DNA obtained by Rosalind Franklin and Maurice Wilkins, established the spatial structure of DNA and put forward a later confirmed assumption about the mechanism of its replication (doubling), which underlies heredity.

1958 year - the formation of the central dogma of molecular biology by Francis Crick: the transfer of genetic information goes in the direction of DNA → RNA → protein.

The essence of the dogma is that cells have a certain directed flow of information from DNA, which, in turn, is the original genetic text, consisting of four letters: A, T, G and C. It is written in the double helix of DNA in the form sequences of these letters - nucleotides.

This text is transcribed. And the process itself is called transcription... In the course of this process, RNA is synthesized, which is identical to the genetic text, but with a difference: in RNA instead of T there is U (uracil).

This RNA is called messenger RNA (mRNA), or matrix (mRNA). Broadcast mRNA is carried out using the genetic code in the form of triplet nucleotide sequences. During this process, the text of DNA and RNA nucleic acids is translated from a four-letter text into a twenty-letter amino acid text.

There are only twenty natural amino acids, and there are four letters in the text of nucleic acids. Because of this, there is a translation from the four-letter alphabet to the twenty-letter alphabet by means of a genetic code in which an amino acid corresponds to every three nucleotides. So you can make as many as 64 three-letter combinations of four letters, while there are 20 amino acids. From this it follows that the genetic code must necessarily have the property of degeneracy. However, at that time the genetic code was not known, moreover, they did not even begin to decipher it, but Crick had already formulated his central dogma.

Nevertheless, there was a belief that the code should exist. By that time, this code had been proven to have tripletness. This means that specifically three letters in nucleic acids ( codons) correspond to any amino acid. There are 64 of these codons, they encode 20 amino acids. This means that several codons correspond to each amino acid at once.

Thus, we can conclude that the central dogma is a postulate that a directed flow of information occurs in the cell: DNA → RNA → protein. Crick emphasized the main content of the central dogma: the reverse flow of information cannot occur, the protein is not able to change genetic information.

This is the main meaning of the central dogma: a protein is not able to change and transform information into DNA (or RNA), the flow always goes only in one direction.

Some time after this, a new enzyme was discovered, which was not known at the time of the formulation of the central dogma, - reverse transcriptasewhich synthesizes DNA from RNA. The enzyme was discovered in viruses in which the genetic information is encoded in RNA, not DNA. These viruses are called retroviruses. They have a viral capsule with RNA and a special enzyme enclosed in it. The enzyme is reverse transcriptase, which synthesizes DNA from the template of this viral RNA, and this DNA then serves as the genetic material for the further development of the virus in the cell.

Of course, this discovery caused great shock and a lot of controversy among molecular biologists, since it was believed that, based on the central dogma, this could not be. However, Crick immediately explained that he never said it was impossible. He only said that there can never be a flow of information from protein to nucleic acids, and already inside nucleic acids of any kind, processes are quite possible: DNA synthesis for DNA, DNA for RNA, RNA for DNA and RNA for RNA.

After the formulation of the central dogma, a number of questions remained: how does the alphabet of four nucleotides that make up DNA (or RNA) encode the 20-letter alphabet of amino acids that make up proteins? What is the essence of the genetic code?

The first ideas about the existence of the genetic code were formulated by Alexander Downs ( 1952 g.) and Georgy Gamov ( 1954 g.). Scientists have shown that the sequence of nucleotides must include at least three links. It was later proved that such a sequence consists of three nucleotides, called codon (triplet). Nevertheless, the question of which nucleotides are responsible for the inclusion of which amino acid in a protein molecule remained open until 1961.

And in 1961 Marshall Nirenberg, together with Heinrich Mattei, used the system to broadcast in vitro... An oligonucleotide was taken as a template. It consisted only of uracil residues, and the peptide synthesized from it included only the amino acid phenylalanine. Thus, for the first time, the codon value was established: the UUU codon encodes phenylalanine. After them, the Har Quran found out that the nucleotide sequence UCUCUCUCUCUC encodes a set of amino acids serine-leucine-serine-leucine. By and large, thanks to the work of Nirenberg and the Koran, to 1965 year the genetic code was completely unraveled. It turned out that each triplet encodes a specific amino acid. And the order of the codons determines the order of the amino acids in the protein.

The main principles of the functioning of proteins and nucleic acids were formulated by the beginning of the 70s. It was recorded that the synthesis of proteins and nucleic acids is carried out by a matrix mechanism. The template molecule carries encoded information about the sequence of amino acids or nucleotides. During replication or transcription, the template is DNA; during translation and reverse transcription, it is mRNA.

Thus, the prerequisites were created for the formation of directions in molecular biology, including genetic engineering. And in 1972, Paul Berg and his colleagues developed a molecular cloning technology. Scientists get the first recombinant DNA in vitro... These outstanding discoveries formed the basis for a new direction in molecular biology, and 1972 the year since then is considered the birth date of genetic engineering.

3. Methods of molecular biology

Colossal advances in the study of nucleic acids, the structure of DNA and protein biosynthesis have led to the creation of a number of methods that are of great importance in medicine, agriculture, and science in general.

After studying the genetic code and the basic principles of storage, transmission and implementation of hereditary information for the further development of molecular biology, it became necessary special methods... These methods would allow genes to be manipulated, modified and isolated.

The emergence of such methods took place in the 1970s and 1980s. This gave a huge impetus to the development of molecular biology. First of all, these methods are directly related to the production of genes and their introduction into the cells of other organisms, as well as the ability to determine the sequence of nucleotides in genes.

3.1. DNA electrophoresis

DNA electrophoresis is the basic method for working with DNA. DNA electrophoresis is used along with almost all other methods to isolate the desired molecules and further analyze the results. The very method of gel electrophoresis is used to separate DNA fragments by length.

Before or after electrophoresis, the gel is treated with dyes that can bind to DNA. The dyes fluoresce in ultraviolet light, resulting in a pattern of bands in the gel. To determine the lengths of DNA fragments, they can be compared with by markers - sets of fragments of standard lengths, which are applied to the same gel.

Fluorescent proteins

When studying eukaryotic organisms, it is handy to use fluorescent proteins as marker genes. Gene of the first green fluorescent protein ( green fluorescent protein, GFP) isolated from jellyfish Aqeuorea victoria, after which they were introduced into various organisms. Then the genes of fluorescent proteins of other colors were isolated: blue, yellow, red. To obtain proteins with properties of interest, such genes were artificially modified.

In general, the most important tools for working with a DNA molecule are enzymes that carry out a number of DNA transformations in cells: DNA polymerase, DNA ligases and restriction enzymes (restriction endonucleases).

Transgenesis

Transgenesis called the transfer of genes from one organism to another. And such organisms are called transgenic.

Recombinant protein preparations are just obtained by transferring genes into the cells of microorganisms. Basically, these protein preparations are interferons, insulin, some protein hormones, and proteins for the production of a number of vaccines.

In other cases, cell cultures of eukaryotes or transgenic animals are used, mostly livestock, which secretes the required proteins into milk. In this way, antibodies, clotting factors and other proteins are obtained. The method of transgenesis is used to obtain crop plants resistant to pests and herbicides, and with the help of transgenic microorganisms, wastewater is purified.

In addition to all of the above, transgenic technologies are indispensable in scientific research, because the development of biology is faster with the use of methods of modification and gene transfer.

Restriction enzymes

The sequences recognized by restriction endonucleases are symmetrical, therefore, all kinds of breaks can occur either in the middle of such a sequence, or with a shift in one or both strands of the DNA molecule.

When any DNA is digested with a restriction enzyme, the sequences at the ends of the fragments will be the same. They will be able to connect again because they have complementary sites.

You can get a single molecule by stitching these sequences using DNA ligases... Due to this, it is possible to combine fragments of two different DNAs and obtain recombinant DNA.

3.2. PCR

The method is based on the ability of DNA polymerases to complete the second strand of DNA along the complementary strand in the same way as in the process of DNA replication in a cell.

3.3. DNA sequencing

The rapid development of the sequencing method makes it possible to effectively determine the characteristics of the organism under study at the level of its genome. The main advantage of such genomic and post-genomic technologies is to increase the possibilities of researching and studying the genetic nature of human diseases in order to take the necessary measures in advance and avoid diseases.

Through large-scale research, it is possible to obtain the necessary data on the various genetic characteristics of different groups of people, thereby developing medical methods. Because of this, the identification of a genetic disposition to various diseases today it is very popular.

Such methods are widely used practically all over the world, including in Russia. Due to scientific progress, such methods are being introduced into medical research and medical practice in general.

4. Biotechnology

Biotechnology - a discipline that studies the possibilities of using living organisms or their systems for solving technological problems, as well as creating living organisms with the desired properties by means of genetic engineering. Biotechnology applies methods of chemistry, microbiology, biochemistry and, of course, molecular biology.

The main directions of development of biotechnology (the principles of biotechnological processes are introduced into the production of all industries):

1. Creation and production of new types of food and animal feed.
2. Obtaining and studying new strains of microorganisms.
3. Breeding new varieties of plants, as well as creating means for protecting plants from diseases and pests.
4. Application of biotechnology methods for environmental needs. Such biotechnology methods are used for waste recycling, cleaning wastewater, exhaust air and soil sanitation.
5. Production of vitamins, hormones, enzymes, serums for the needs of medicine. Biotechnologists are developing improved medicationsthat were previously considered incurable.

Genetic engineering is a major advance in biotechnology.

Genetic Engineering - a set of technologies and methods for producing recombinant RNA and DNA molecules, isolating individual genes from cells, manipulating genes and introducing them into other organisms (bacteria, yeast, mammals). Such organisms are capable of producing end products with the desired, altered properties.

Genetic engineering methods are aimed at constructing new, previously non-existent combinations of genes in nature.

Speaking about the achievements of genetic engineering, it is impossible not to touch upon the topic of cloning. Cloning is one of the methods of biotechnology used to obtain identical descendants of different organisms through asexual reproduction.

In other words, cloning can be thought of as the process of creating genetically identical copies of an organism or cell. And cloned organisms are similar or completely identical, not only in external signs, but also in terms of genetic content.

Dolly the notorious sheep became the first cloned mammal in 1966. It was obtained by transplanting the nucleus of a somatic cell into the cytoplasm of the egg. Dolly was a genetic copy of a nuclear donor sheep. Under natural conditions, an individual is formed from one fertilized egg, having received half of the genetic material from two parents. However, during cloning, the genetic material was taken from the cell of one individual. First, the nucleus was removed from the zygote, in which the DNA itself is located. After that, the nucleus was removed from the cell of an adult sheep and implanted into that zygote devoid of a nucleus, and then it was transplanted into the uterus of an adult and provided an opportunity for growth and development.

However, not all cloning attempts have been successful. In parallel with Dolly's cloning, a DNA replacement experiment was performed on 273 other eggs. But only in one case was a living adult animal able to fully develop and grow. After Dolly, scientists tried to clone other types of mammals.

One of the types of genetic engineering is genome editing.

The CRISPR / Cas tool is based on an element of the immune defense system of bacteria, which scientists have adapted to introduce any changes in the DNA of animals or plants.

CRISPR / Cas is one of the biotechnological methods for manipulating individual genes in cells. There are many applications for this technology. CRISPR / Cas allows researchers to figure out the function of different genes. To do this, you just need to cut the gene under study from the DNA and study which functions of the body were affected.

Some practical applications of the system:

1. Agriculture. Agricultural crops can be improved through CRISPR / Cas systems. Namely, to make them tastier and more nutritious, as well as heat-resistant. It is possible to endow plants with other properties: for example, to cut out an allergen gene from nuts (peanuts or hazelnuts).
2. Medicine, hereditary diseases. Scientists have the goal of using CRISPR / Cas to remove mutations from the human genome that can lead to diseases such as sickle cell anemia, etc. In theory, CRISPR / Cas can stop the development of HIV.
3. Gene drive. CRISPR / Cas can change not only the genome of an individual animal or plant, but also the gene pool of a species. This concept is known as "Gene drive"... Every living organism transfers half of its genes to its offspring. But the use of CRISPR / Cas can increase the probability of gene transfer by up to 100%. This is important in order for the desired trait to spread faster throughout the population.

Swiss scientists have significantly improved and modernized the CRISPR / Cas genome editing method, thereby expanding its capabilities. However, scientists could only modify one gene at a time using the CRISPR / Cas system. But now researchers at the Swiss Higher Technical School of Zurich have developed a method with which it is possible to simultaneously modify 25 genes in a cell.

For the latest technique, specialists used the Cas12a enzyme. For the first time in history, geneticists have successfully cloned monkeys. Popular Mechanics;